If you're talking about cobblestone:
* Smooth: A smooth surface is the opposite of a rough, cobblestone surface.
* Paved: A paved road uses smooth materials like asphalt or concrete instead of cobblestones.
* Asphalt: This is a specific material used to create smooth, paved surfaces.
If you're talking about cobbling together something:
* Well-crafted: Cobbled-together things are often makeshift or poorly made, so the opposite would be something well-crafted or expertly constructed.
* Professional: If something is cobbledtogether, it might be done in a quick and informal way. The opposite would be a professional, polished job.
If you're talking about a type of stone:
* Granite: Cobblestones are usually made of smaller stones, while granite is a large, solid type of stone.
* Smooth stone: Cobblestones are rough, while smooth stones have a polished surface.
Ultimately, the best opposite for "cobble" depends on the specific context.